1. Field of the Invention
The present invention relates to a method and apparatus for reporting CQI/CSI measurement information efficiently.
2. Description of the Related Art
The mobile communication system has been developed for the user to communicate on the move. With the rapid advance of technologies, the mobile communication system has evolved to the level capable of providing high speed data communication service as well as voice telephony service.
Recently, as one of the next generation mobile communication system, Long Term Evolution (LTE) is on the standardization by the 3rd Generation Partnership Project (3GPP). LTE is a technology designed to provide high speed packet-based communication of up to 100 Mbps and aims at commercial deployment around 2010 timeframe. In order to accomplish the aim, a discussion is being held on several schemes: one scheme for reducing the number of nodes located in a communication path by simplifying a configuration of the network, and another scheme for maximally approximating wireless protocols to wireless channels.
Meanwhile, unlike voice service, the data service is provided on the resource determined according to the data amount to be transmitted and channel condition. Accordingly, the wireless communication system, especially cellular communication, is provided with a scheduler manages transmission resource allocation in consideration of the required resource amount, channel condition, data amount, etc. This is the fact in the LTE system as the next generation mobile communication system, and the scheduler located at the base station manages the transmission resource allocation.
Recent studies are focused on the LTE-Advanced (LTE-A) for improving data rate with the adaptation of several new techniques to legacy LTE system. For such a leap in technology, Inter-Cell Interference Coordination (ICIC) is also evolving to enhanced ICIC (eICIC) or Time-domain ICIC. The eICIC/Time-domain ICIC is a technique to mitigate inter-cell interference to the victim cell by reducing transmit power in a cell causing interference or totally muting data transmission in unit of subframe.
The UE located in the victim cell can have an opportunity for channel measurement to maintain the radio link to the victim cell and transmit data only in the corresponding subframe. This subframe is referred to as Almost Blank Subframe (ABS) and appears in a predetermined pattern.
The ABSs are offered in various patterns, particularly, two ABS patterns for CQI/CSI measurement. These patterns are notified to the UE through RRC signal. The UE has to perform CQI/CSI report with one of these two patterns. There is therefore a need of a method for determining the pattern to be applied.